import os, uuid

def generate(filename, depth=2, base=512):
    if os.path.sep in filename:
        path, filename = os.path.split(filename)
    else:
        path = None
    dummyhash = sum(ord(c)*256**(i % 4) for i,c in enumerate(filename)) % base**depth
    folders = []
    for level in range(depth-1,-1,-1):
        code, dummyhash = divmod(dummyhash, base**level)
        folders.append("%03x" % code)
    folders.append(filename)
    if path:
        folders.insert(0,path)
    return os.path.join(*folders)

def exists(filename, path=None):
    if os.path.exists(filename):
        return True
    if path is None:
        path, filename = os.path.split(filename)
    fullfilename = os.path.join(path, generate(filename))
    if os.path.exists(fullfilename):
        return True
    return False

def remove(filename, path=None):
    if os.path.exists(filename):
        return os.unlink(filename)
    if path is None:
        path, filename = os.path.split(filename)
    fullfilename = os.path.join(path, generate(filename))
    if os.path.exists(fullfilename):
        return os.unlink(fullfilename)
    raise IOError

def open(filename, mode="r", path=None):
    if not path:
        path, filename = os.path.split(filename)
    fullfilename = None
    if not mode.startswith('w'):
        fullfilename = os.path.join(path, filename)
        if not os.path.exists(fullfilename):
            fullfilename = None
    if not fullfilename:
        fullfilename = os.path.join(path, generate(filename))
        if mode.startswith('w') and not os.path.exists(os.path.dirname(fullfilename)):
            os.makedirs(os.path.dirname(fullfilename))
    return file(fullfilename, mode)

def test():
    if not os.path.exists('tests'):
        os.mkdir('tests')
    for k in range(20):
        filename = os.path.join('tests',str(uuid.uuid4())+'.test')
        open(filename, "w").write('test')
        assert open(filename, "r").read()=='test'
        if exists(filename):
            remove(filename)

if __name__ == '__main__':
    test()
